Sulfide oxidation in fluidized bed bioreactor using nylon support material

A continuous fluidized bed bioreactor (FBBR) with nylon support particles was used to treat synthetic sulfide wastewater at different hydraulic retention time of 25, 50 and 75 min and upflow velocity of 14, 17 and 20 m/hr. The effects of upflow velocity, hydraulic retention time and reactor operation time on sulfide oxidation rate were studied using statistical model. Mixed culture obtained from the activated sludge, taken from tannery effluent treatment plant, was used as a source for microorganisms. The diameter and density of the nylon particles were 2-3 mm and 1140 kg/m³, respectively. Experiments were carried out in the reactor at a temperature of (30 ± 2)℃, at a fixed bed height of 16 cm after the formation of biofilm on the surface of support particles. Biofilm thickness reached (42 ± 3) μupm after 15 days from reactor start-up. The sulfide oxidation, sulfate and sulfur formation is examined at all hydraulic retention times and upflow velocities. The results indicated that almost 90%-92% sulfide oxidation was achieved at all hydraulic retention times. Statistical model could explain 94% of the variability and analysis of variance showed that upflow velocity and hydraulic retention time slightly affected the sulfide oxidation rate. The highest sulfide oxidation of 92% with 70% sulfur was obtained at hydraulic retention time of 75 min and upflow velocity of 14 m/hr.     

Bamboo charcoal enhances cellulase and urease activities during chicken manure composting: Roles of the bacterial community and metabolic functions

Microbial enzymes are crucial for material biotransformation during the composting process. In this study, we investigated the effects of adding bamboo charcoal (BC) (i.e., at 5%, 10%, and 20% corresponding to BC5, BC10, and BC20, respectively) on the enzyme activity levels during chicken manure composting. The results showed that BC10 could increase the cellulose and urease activities by 56% and 96%, respectively. The bacterial community structure in BC10 differed from those in the other treatments, and Luteivirga, Lactobacillus, Paenalcaligenes, Ulvibacter, Bacillus, Facklamia, Pelagibacterium, Sporosarcina, Cellvibrio, and Corynebacterium had the most important roles in composting. Compared with other treatments, BC10 significantly enhanced the average rates of degradation of carbohydrates (D-xylose (40%) and α-D-lactose (44%)) and amino acids (L-arginine (16%), L-asparagine (14%), and L-threonine (52%)). We also explored the associations among the bacterial community and their metabolic functions with the changes in the activities of enzymes. Network analysis demonstrated that BC10 altered the co-occurrence patterns of the bacterial communities, where Ulvibacter and class Bacilli were the keystone bacterial taxa with high capacities for degrading carbon source, and they were related to increases in the activities of cellulase and urease, respectively. The results obtained in this study may help to further enhance the efficiency of composting.     

Brilliant red X-3B uptake by a novel polycyclodextrin-modified magnetic cationic hydrogel: Performance, kinetics and mechanism

A novel polycyclodextrin-modified magnetic cationic hydrogel (PCD-MCH) was developed and its performance, kinetics and mechanism for the removal of reactive brilliant red X-3B (X-3B) were studied. The results showed that the zeta-potential of PCD-MCH was 32.8 to 16.7 mV at pH 3.0–10.5. The maximum X-3B adsorption capacity of PCD-MCH was 2792.3 mg/g. The adsorption kinetics could be well-described by the Weber–Morris model and the homogeneous surface diffusion model (HSDM). Diffusion stages corresponding to surface or film diffusion, intra-particle or wide mesopore diffusion, and narrow mesopore/micropore diffusion occurred at 0–120, 120–480 and 480–1200 min, respectively. The latter two diffusion stages were rate-controlling for X-3B adsorption kinetics. At the initial X-3B concentration of 600 mg/L, the diffusion coefficient (D_s) and external mass transfer coefficient in the liquid phase (k_F) were 3 × 10^?11 cm²/min and 4.68 × 10^?6 cm/min, respectively. X-3B approaching the center of PCD-MCH particles could be observed at 360 min. At the end of the third diffusion stage, the C_p at q/q_e = 0 was 45.20 mg/L, which was close to the homogeneous C_p value of 46 mg/L along the radius of PCD-MCH particles. At pH 3.0–10.0, PCD-MCH showed stable X-3B adsorption capacities. After five regeneration-reuse cycles, the residual adsorption capacity of regenerated PCD-MCH was higher than 892.7 mg/g. The corresponding adsorption mechanism was identified as involving electrostatic interactions, cyclodextrin cavities and hydrogen bonds, of which cyclodextrin cavities showed prominent capture performance towards dye molecules through the formation of inclusion complexes.     

A novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) for advanced nitrogen removal from domestic sewage

To achieve advanced nitrogen removal from actual municipal sewage, a novel multistage anoxic/aerobic process with sludge regeneration zone (R-MAO) was developed. The reactor was used to treat actual domestic sewage and the nitrogen removal capacity of the sludge regeneration zone (R zone) was investigated during the long-term operation. The best performance was obtained at the R zone's Oxidation-Reduction Potential (ORP) of -50±30 mV and hydraulic residence times (HRT) of 1.2 hr. The average effluent COD, TN, NH₄⁺-N and NO₃⁻-N of the R-MAO process were 18.0±2.3, 7.5±0.6, 1.0±0.5 and 4.6±0.4 mg/L, respectively, with the corresponding removal efficiency of COD, TN and NH₄⁺-N were 92.9%±1.0%, 84.1%±1.5% and 97.5%±1.1%. Compared to the sole MAO system, the TN removal efficiency of the R-MAO increased by 10.1%. Besides, under the optimal conditions, the contribution of the R zone in the R-MAO that removal COD, TN, NH₄⁺-N and NO₃⁻-N were 0.36, 0.15, 0.032 and 0.82 g/day. High-throughput sequencing results showed that uncultured_bacterium_f_Burkholderiaceae (5.20%), OLB8 (1.04%) and Ottowia (1.03%) played an important role in denitrification in the R zone. This study provided effective guidance for the design and operation of the R-MAO process in domestic sewage treatment.     

Sulfate reduction behavior in pressure-bearing leachate saturated zone

Attention should be paid to the sulfate reduction behavior in a pressure-bearing leachate saturated zone. In this study, within the relative pressure range of 0–0.6 MPa, the ambient temperature with the highest sulfate reduction rate of 50°C was selected to explore the difference in sulfate reduction behavior in a pressure-bearing leachate saturated zone. The results showed that the sulfate reduction rate might further increase with an increase in pressure; however, owing to the effect of pressure increase, the generated hydrogen sulfide (H₂S) could not be released on time, thereby decreasing its highest concentration by approximately 85%, and the duration extended to about two times that of the atmospheric pressure. Microbial community structure and functional gene abundance analyses showed that the community distribution of sulfate-reducing bacteria was significantly affected by pressure conditions, and there was a negative correlation between disulfide reductase B (dsrB) gene abundance and H₂S release rate. Other sulfate reduction processes that do not require disulfide reductase A (dsrA) and dsrB genes may be the key pathways affecting the sulfate reduction rate in the pressure-bearing leachate saturated zone. This study improves the understanding of sulfate reduction in landfills as well as provides a theoretical basis for the operation and management of landfills.     

Bamboo charcoal addition enhanced the nitrogen removal of anammox granular sludge with COD: Performance, physicochemical characteristics and microbial community

The effects of different chemical oxygen demand (COD) concentrations on the anammox granular sludge with Bamboo Charcoal (BC) addition were evaluated in UASB reactor. The results showed that the average total nitrogen (TN) removal efficiency was reduced from 85.9% to 81.4% when COD concentration was increased from 50 to 150 mg/L. However, the TN removal efficiency of BC addition reactors was dramatically 3.1%–6.4% higher than that without BC under different COD concentrations. The average diameter of granular sludge was 0.13 mm higher than that without BC. The settling velocity was increased by elevated COD concentration, while the EPS and VSS/SS were increased with BC addition. The high-throughput Miseq sequencing analyses revealed that the bacterial diversity and richness were decreased under COD addition, and the Planctomycetes related to anammox bacteria were Candidatus Brocadia and Candidatus Kuenenia. The Metagenomic sequencing indicated that the abundance of denitrification related functional genes all increased with elevated COD, while the abundance of anammox related functional genes of decreased. The functional genes related to anammox was hydrazine synthase encoding genes (hzsA, hzsB and hzsB). The average relative abundance of hzs genes in the reactor with BC addition was higher than the control at COD concentrations of 50 mg/L and 150 mg/L. The functional genes of denitrification mediated by BC were higher than those without BC throughout the operation phase. It is interesting to note that BC addition greatly enriched the related functional genes of denitrification and anammox.     

Nitrite pre-treatment of dewatered sludge for microbial fuel cell application

The effect of pre-treatment of dewatered sludge using different nitrite concentrations and pH for microbial fuel cell (MFC) application was investigated. The results show that the addition of nitrite was feasible to increase the solubilization rate of the sludge and may reduce mass transfer limitation at the anode. This helped the MFC to reach higher voltage and to generate more power. The higher free nitrous acid (FNA) concentration under the acidic condition helped to increase sludge solubilization. However, under an alkaline condition, during which the FNA concentration was relatively low, the solubilization of the sludge was higher. The highest voltage and power density produced was 390?mV and 153?mW/m², respectively, with the addition of nitrite at 100?mg-N/L and pH?9. Furthermore, it was found that elevated levels of FNA could inhibit electrogenic bacteria thus reducing power generation.     

Effect of aeration rate on composting of penicillin mycelial dreg

Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90 L/(min·kg) organic matter(OM) were examined. The principal physicochemical parameters were monitored during the 32 day composting period. Results showed that the higher aeration rate of 0.90 L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation;but the lower aeration rate of 0.15 L/(min·kg) did induce an accumulation of NH+4-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures ≥ 55°C, the maximum NO-3-N content and seed germination, and the minimum C/N ratio were obtained with 0.50 L/(min·kg) OM. Therefore, aeration rates of0.50 L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.     

Physiological and biochemical characteristic of Miscanthus × giganteus grown in heavy metal – oil sludge co-contaminated soil

The effect of oil sludge and zinc, present in soil both separately and as a mixture on the physiological and biochemical parameters of Miscanthus × giganteus plant was examined in a pot experiment. The opposite effect of pollutants on the accumulation of plant biomass was established: in comparison with uncontaminated control the oil sludge increased, and Zn reduced the root and shoot biomass. Oil sludge had an inhibitory effect on the plant photosynthetic apparatus, which intensified in the presence of Zn. The specific antioxidant response of M. × giganteus to the presence of both pollutants was a marked increase in the activity of superoxide dismutase (mostly owing to oil sludge) and glutathione-S-transferase (mostly owing to zinc) in the shoots. The participation of glutathione-S-transferase in the detoxification of both the organic and the inorganic pollutants was assumed. Zn inhibited the activity of laccase-like oxidase, whereas oil sludge promoted laccase and ascorbate oxidase activities. This finding suggests that these enzymes play a part in the oxidative detoxification of the organic pollutаnt. With both pollutants used jointly, Zn accumulation in the roots increased 6-fold, leading to increase in the efficiency of soil clean-up from the metal. In turn, Zn did not significantly affect the soil clean-up from oil sludge. This study shows for the first time the effect of co-contamination of soil with oil sludge and Zn on the physiological and biochemical characteristics of the bioenergetic plant M. × giganteus. The data obtained are important for understanding the mechanisms of phytoremediation with this plant.     

Kinetic and mechanism studies of the ozonolysis of three unsaturated ketones

Reaction rate constants and products of 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene (FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure. The rate constants were (1.09 ± 0.12) × 10^?17, (3.48 ± 0.36) × 10^?17 and (5.70 ± 0.60) × 10^?17 cm³/(molecule?sec), respectively. According to the obtained rate constants, the effects of carbonyl were discussed. The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond, then causing the decline of rate constants. The quantum chemical calculation was used to explain the results of rate constants. The products of ozonolysis were mainly aldehydes, which have significant influence on the formation of SOA, and hence play an important role in the atmosphere. In this work, we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations. Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4, 11.4 and 6.9 hr for 1-octen-3-one, 3-octen-2-one and 4-hexen-3-one, respectively.     

土壤整体质量的生态毒性评价

土壤样品采自沈阳西部污灌区 .进行了污染物 (重金属和矿物油 )含量分析和生态毒性试验 .重金属采用原子吸收分光光度仪测定 ,矿物油采用紫外分光光度计测定 .生态毒性试验分别参照国际标准组织 (ISO)和OECD指南 ,进行了植物毒性试验、蚯蚓毒性试验和蚕豆根尖微核试验 .植物试验以小麦种子发芽根伸长抑制率为试验终点 ,试验周期50h ,蚯蚓毒性试验以蚯蚓死亡率、体重增长抑制率为试验终点 ,试验周期28d .土壤中矿物油含量在145mg/kg～1121mg/kg ,重金属Cd为0.34mg/kg～1.81mg/kg .土壤对植物和蚯蚓显示不同程度的毒性效应 ,土壤的蚕豆根尖微核率明显高于对照 .种子发芽根伸长抑制率为2.0%至-35.1% ,蚯蚓死亡率为0%～40%.体重增长抑制率由14d的-2.3%～-19.4%在28d增加到-2.1%～10.7% ,蚕豆根尖微核率最高达6.62/100.研究表明 ,土壤中的污染物积累较低 ,但具有明显的生态毒性 .     

国际化学危险品分类体系简介

介绍了当前国际化学危险品的各种分类体系,对比了GHS与TDG、EU_CLP、DOT、WHMIS等对化学危险品的具体分类。有助于GHS的理解与掌握,全面推进GHS在我国的实施。     

多目标规划在预测区域总产值-排污-水质协调解中的应用研究

以某区域水环境－经济系统为研究实例，寻求值－排污－水质综合协调解方法，寻求净收益最大时的总体规划方案。建立目标参数规划模型，寻求不同生产规模条件下的产值－排污－水质协调解，又探讨了水环境标准约束下的某化工区废水治理费用的计算方法，提出了以供决策者选择的方案。     

滇池富营养化特性评价

介绍了滇池水质状况,对滇池富营养化特性进行了分析和评价,并提出了对策.     

生态保护地协同管控成效评估

分区分类管理是我国生态保护的重要管控制度,生态保护地是事关国家生态安全的关键区域,开展生态保护地保护成效评估及不同类型生态保护地之间的协同管控成效评估具有重要意义。以吉林省自然保护地和重点生态功能区等生态保护地（即禁止开发区和限制开发区）为研究对象,以重要生态空间、植被生态、水源涵养功能为主要内容,基于“禁止开发区—限制开发区—省域”的管控梯度差异,评估分析了生态保护地的协同管控成效。结果表明：（1）从重要生态空间协同管控成效来看,自然保护地的重要生态空间面积比例最高、人类活动干扰指数最低,这与生态保护管控严格程度呈现很好地正相关。但是1980—2015年间重要生态空间面积比例均有所减少,减少幅度与管控严格程度没有表现出正相关。（2）从植被生态协同管控成效来看,植被覆盖总体呈现出自东向西逐步降低的特点,与东部分布有重点生态功能区和森林类自然保护区、西部分布较多的湿地类自然保护地的空间特征一致。但是,由于湿地及水域类型自然保护地面积占比较高,且分布在吉林西部草原和平原区的面积比例较高,自然保护地的年际变化较大、且植被覆盖稳定度低于重点生态功能区。（3）从水源涵养功能协同管控成效来看,水源涵养能力呈现出东部和西部高、中部低的特点,与这两个区域主要分布有森林、草地和湿地等重要生态空间密切相关,也与分布着大面积的重点生态功能区和各类自然保护地密切相关。自然保护区的水源涵养能力最高,且年际变化最小、稳定性最高。     

氯苯类化合物的生物降解

经过2个月的驯化,从某染料厂和某毛纺厂活性污泥中分离出能够生长于1,4-二氯苯、1,2,4-三氯苯和六氯苯的4种微生物.通过测定该混合菌降解氯苯类化合物过程中的累积好氧量、微生物生长曲线及降解产物Cl^-的释放,证明在好氧条件下该混合菌能够以1,4二氯苯和1,2,4-三氯苯为唯一碳源和能源,降解产物Cl^-浓度的变化与微生物生长周期有关.通过好氧振荡瓶培养法测得3种氯苯的生物降解顺序为:1,4-二氯苯[356.7μg/(L·d)]>1,2,4-三氯苯[110.4μg/(L·d)]>六氯苯[～6μg/(L·d)],说明氯取代数越多,氯苯类化合物越难被好氧降解.     

燃煤电厂脱硫副产物资源化利用可行性分析——上海案例研究

未来5年(2006～2010年)上海进行脱硫的机组将达957.2万kW,文章对上海市未来5年中脱硫副产物的资源化利用,进行了技术、经济分析,预计每年可节省SO2排污费用约1.02、1.28亿元,如以原煤计,则为1.51亿元/a和1.89亿元/a,到2010年将达1.67～2.09亿元/a,折成原煤则为2.34～2.93亿元/a,如排污费提高,效益还将扩大;电厂脱硫石膏销售将获得约2160～2880万元/a,折算成原煤应为3024万元/a和4032万元/a,如加工成球或利用余热烘干成粉,利润还会增加;到2010年脱硫石膏销售收入还将进一步放大。上海石膏板或水泥企业利用54～72万t的脱硫石膏,可使企业的原料购买成本节约3250～3650万元/a,如将FGD石膏40%SO3含量与天然石膏34%相比算入成本,使用FGD石膏的水泥生产企业原料购置费节约将更显著。     

哈尔滨松北区城市湿地的生态安全分析

以哈尔滨松北区城市湿地为研究对象,选择10个指标,采用因子分析法和聚类分析法,研究了松花江发生污染事故前后城市湿地的生态安全状况.结果表明:发生污染前哈尔滨松北区城市湿地东区的生态安全程度最高,发生污染后中区的生态安全程度最低;西区的抗干扰能力较差.各主因子中以水因子的下降幅度最大,说明水污染直接影响了哈尔滨松北区城市湿地的生态安全.最后有针对性地提出了哈尔滨松北区城市湿地的生态安全对策.      

后勤装备防腐涂层加速试验环境谱研究

结合后勤装备服役特点,综合考虑亚热带沿海地区湿热、紫外光照、盐雾等主要腐蚀因素的影响,建立了适用于后勤装备表面涂层的加速试验环境谱,给出了各环境块的具体确定方法,并且提出了建立加速谱与装备实际使用环境的当量加速关系的方法。为后勤装备外露关键部位涂层使用寿命评定、涂层有效性检验和腐蚀修理方案制定提供了重要的依据。     

乌海市城区环境噪声现状分析

对乌海市《城市区域环境噪声标准》适用区域进行了划分,以乌海市2011年城区环境噪声监测统计数据为基础,分析了乌海市暴露在不同等效声级下的城区面积分布状况和达标情况。